The present invention relates to the field of turbofan aircraft engines.
It relates more precisely to a relief device for a turbojet and to a turbojet fitted with such a relief device.
In a known manner, an aircraft turbofan engine comprises a main stream of gas flow and a by-pass stream of gas flow that are separated by an intermediate casing that is a structural part. In the main stream are placed, from upstream to downstream in the direction of flow of the gases, a low-pressure compressor and a high-pressure compressor. The air thus compressed is carried to a combustion chamber in which it is mixed with the pressurized fuel that is burnt to supply, downstream of the combustion chamber, energy to a high-pressure turbine that drives the high-pressure compressor, then to a low-pressure turbine that drives the fan and the low-pressure compressor. The gases leaving the turbines supply a residual thrust that is added to the thrust generated by the gases traveling in the by-pass stream in order to provide the propulsion of the aircraft.
In certain flight conditions, the quantity of air delivered by the low-pressure compressor is too great to ensure correct operation of the turbojet, so it is necessary to divert a portion of this air toward the by-pass stream in order to prevent the occurrence of the phenomenon called pumping that is due to the separation of fluid wisps along the blades and causes an instability of the flow.
The air diversion is also called air relief. It is carried out by means of a relief device.